Low Battery Seawall Repair

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  • Location

    Charleston, SC, USA
  • Year

    2020
  • Products

  • Owner

    City of Charleston
  • Engineer

    Johnson, Mirmiran and Thompson (JMT)
  • Contractor

    Gulf Stream Construction Palmetto Gunite
  • Distributor

    New South Supply

Description

The Low Battery seawall is one of Charleston’s most iconic and historic landmarks. The wall was constructed in the early twentieth century along Charleston’s southernmost peninsula between Tradd Street and the “Turn” at White Point Garden. The wall facilitated a large land reclamation project creating what is now known as Murray Boulevard. A waterfront promenade along its length gives pedestrians unobstructed views of the Ashley River.

The concrete seawall, cast on top of timber piling, was exhibiting deterioration of the concrete face and timber piling connections. Settlement behind the wall caused a severe slope in the promenade making it difficult for the public to enjoy its full use and made accessibility a challenge for the City’s disabled residents and visitors. With an increase in sea levels, higher tides, and more intense storms, the existing wall’s frequent overtops contribute to the problematic flooding of the peninsula. 

The Low Battery seawall repairs, designed by Johnson, Mirmiran & Thompson (JMT), included raising the height of the wall, underpinning the wall with micropiles, constructing a new concrete pile cap tied to the existing wall, replacing lost fill material, reconstructing the face and supporting the new ADA-compliant promenade on the pile caps to prevent future settlement. JMT selected GFRP reinforcing bars to reinforce the new concrete promenade, concrete rail posts, and the shotcrete repairs to the walls facing the Ashley River, since these elements would be exposed to the most corrosive environments. 

Gulfstream Construction and their subcontractor Palmetto Gunite completed Phase 1 from Tradd Street to Rutledge Avenue in 2020. Gulfstream selected the Fiberglas™ GFRP rebar supplied by Owens Corning from their plant in Blythewood, South Carolina.

Details

Phase 1 is 865 LF (total project to be approximately 5,000 LF)